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United States Patent |
6,071,560
|
Braendle
,   et al.
|
June 6, 2000
|
Tool with tool body and protective layer system
Abstract
A tool has a tool body and a wear resistant layer system, which layer
system has at least one layer of MeX. Me comprises titanium and aluminum
and X is nitrogen or carbon. The tool has a tool body of high speed steel
(HSS) or of cemented carbide, but it is not a solid carbide end mill and
not a solid carbide ball nose mill. In the MeX layer, the quotient Q.sub.I
as defined by the ratio of the diffraction intensity I(200) to I(111)
assigned respectively to the (200) and (111) plains in the X ray
diffraction of the material using .theta.-2.theta. method is selected to
be .gtoreq.1. Further, the I(200) is at least twenty times larger than the
intensity average noise value, both measured with a well-defined equipment
and setting thereof.
Inventors:
|
Braendle; Hans (Sargans, CH);
Shima; Nobuhiko (Narita, JP)
|
Assignee:
|
Balzers Aktiengesellschaft (Fuerstentum, LI)
|
Appl. No.:
|
928652 |
Filed:
|
September 12, 1997 |
Current U.S. Class: |
427/249.19; 204/192.38; 427/255.394; 427/580 |
Intern'l Class: |
C23C 014/14 |
Field of Search: |
427/580,249,255.2,249.19,255.394
204/197.38
|
References Cited
U.S. Patent Documents
5126030 | Jun., 1992 | Tamagaki et al. | 204/192.
|
Foreign Patent Documents |
0 448 720 A1 | Apr., 1991 | EP.
| |
0 701 982 A1 | Mar., 1996 | EP.
| |
8-209335 | Aug., 1996 | JP.
| |
Other References
Average Energy Deposited Per Atom: A Universal Parameter For Describing
Ion-Assisted Film Growth; Petrov et al.; Applied Physics Letters, Jul. 5,
1993, pp. 36-38.
Titanium Aluminum Nitride Films: A New Alternative to TiN Coatings; Muenz;
Journal Of Vacuum Science & Technology, Nov.-Dec. 1986, pp. 2717-2225.
Interrelationship Between Processing, Coating Properties And Functional
Properties of Steered ARC Physically Vapour Deposited (Ti,Al)N And
(Ti,Nb)N Coatings; Roos et al.; Elsevier Sequoia; Dec. 1, 1990; pp.
547-556.
Effects Of R.F. Bias And Nitrogen Flow Rates On The Reactive Sputtering Of
TiAlN Films; Shew et al.; Elsevier; 1997; pp. 212-219 no month.
Effects of High-Flux Low-Energy (20-100 eV) Ion Irradiation During
Deposition On The Microstructure And Preferred Orientation of TI.sub.0.5
Al.sub.0.5 N Alloys Grown By Ultra-High-Vacuum Reactive Magnetron
Sputtering; Adibi et al.; Journal of Applied Physics, Jun. 15, 1993; pp.
8580-8589.
The Structure And Composition Of Ti-Zr-N, Ti-Al-Zr-N and Ti-Al-V-N
Coatings, Knotek et al.; Materials Science and Engineering, 1988; pp.
481-488 (no month).
|
Primary Examiner: Meeks; Timothy
Attorney, Agent or Firm: Evenson, McKeown, Edwards & Lenahan, P.L.L.C.
Claims
What is claimed is:
1. A method for producing a tool comprising a tool body and a
wear-resistant layer system having at least one hard material layer,
comprising the steps of
(a) reactive PVD depositing said at least one hard material layer on said
tool body in a vacuum chamber,
(b) adjusting a partial pressure of a reactive gas for said reactive PVD
depositing, either alone or in combination with also adjusting a bias
voltage of the tool body with respect to a predetermined reference
potential, for said reactive PVD depositing so as to obtain a desired
Q.sub.I value for said at least one hard material layer, said adjusting
being performing based upon an interdependency of said bias voltage and of
said partial pressure with respect to control of Q.sub.I value of said at
least one hard material layer as follows:
(i) an increase of said bias voltage leads to a reduction of said Q.sub.I
value and a decrease of said bias voltage leads to an increase of said
Q.sub.I value and,
(ii) a reduction of said partial pressure leads to a reduction of said
Q.sub.I value and an increase of said partial pressure leads to an
increase of said Q.sub.I value.
2. The method of claim 1, where the step (b) comprises reducing said
partial pressure for reducing said Q.sub.I value.
3. The method of claim 1, wherein the step (b) comprises increasing said
bias voltage for reducing said Q.sub.I value.
4. The method of claim 1, where the step (b) comprises reducing said
pressure and increasing said bias voltage for reducing said Q.sub.I value.
5. The method of claim 1, further comprising the step of performing said
reactive PVD deposition by reactive cathodic arc evaporation.
6. The method of claim 5, further comprising the step of magnetically
controlling said arc evaporation.
7. The method of claim 1, wherein the at least one hard material layer
comprises an MeX layer, wherein Me comprises titanium and aluminum and X
is at least one of nitrogen and carbon and is introduced into said PVD
depositing by reactive gas.
8. The method of claim 7, said desired Q.sub.I value is
.gtoreq.2.
9. The method of claim 8 wherein said desired Q.sub.I value is
.gtoreq.10.
10. The method of claim 7, wherein said desired Q.sub.I value is .gtoreq.5.
11. The method of claim 1, wherein said tool body is of one of the
materials
high speed steel (HSS)
cemented carbide
and wherein said tool is not a solid carbide end mill and not a solid
carbide ball nose mill and said desired Q.sub.I value is .gtoreq.1.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
The subject matter of U.S. Pat. No. 5,709,784 is incorporated by reference
herein.
The present invention is directed on a tool with a tool body and a wear
resistant layer system, wherein the layer system comprises at least one
layer of MeX, wherein
Me comprises titanium and aluminum,
X is at least one of nitrogen and of carbon.
Definition
The term Q.sub.I is defined as the ratio of the diffraction intensities
I(200) to I(111), assigned respectively to the (200) and (111) plains in
the X ray diffraction of a material using the .theta.-2.theta. method.
Thus, there is valid Q.sub.I =I(200)/I(111). The intensity values were
measured with the following equipment and with the following settings:
Siemens Diffractometer D500
Power:
Operating voltage: 30 kV
Operating current: 25 mA
Aperture Diaphragms:
Diaphragm position I: 1.degree.
Diaphragm position II: 0.1.degree.
Detector Diaphragm: Soller slit
Time constant: 4 s
2.theta. angular speed: 0.05.degree./min
Radiation: Cu-K.alpha.(0.15406 nm)
When we refer to "measured according to MS" we refer to this equipment and
to these settings. Thereby, all quantitative results for Q.sub.I and I
throughout this application have been measured by MS.
We understand by "tool body" the uncoated tool.
We understand under "hard material" a material with which tools which are
mechanically and thermally highly loaded in operation are coated for wear
resistance. Preferred examples of such materials are referred to below as
MeX materials.
It is well-known in the tool-protecting art to provide wear resistant layer
systems which comprise at least one layer of a hard material, as defined
by MeX.
The present invention has the object of significantly improving the
lifetime of such tools. This is resolved by selecting for said at least
one layer a Q.sub.I value, for which there is valid
Q.sub.I .gtoreq.1
and wherein the tool body is made of high speed steel (HSS) or of cemented
carbide, whereby said tool is not a solid carbide end mill or a solid
carbide ball nose mill. Further, the value of I(200) is higher by a factor
of at least 20 than the intensity noise average level as measured
according to MS.
According to the present invention it has been recognised that the Q.sub.I
values as specified lead to an astonishingly high improvement of wear
resistance, and thus of lifetime of a tool, if such a tool is of the kind
as specified.
Up to now, application of a wear resistant layer systems of MeX hard
material was done irrespective of interaction between tool body material
and the mechanical and thermal load the tool is subjected to in operation.
The present invention thus resides on the fact that it has been recognised
that an astonishing improvement of wear resistance is realised when
selectively combining the specified Q.sub.I value with the specified kind
of tools, thereby realising a value of I(200) higher by a factor of at
least 20 than the average noise intensity level, both measured with MS.
With respect to inventively coating cemented carbide tool bodies, it has
further been recognised that a significant improvement in lifetime is
reached if such cemented carbide tools are inserts, drills or gear cutting
tools, as e.g. hobs or shaper cutters, whereby the improvement is
especially pronounced for such inserts or drills.
The inventively reached improvement is even increased if Q.sub.I is
selected to be at least 2, and an even further improvement is realised by
selecting Q.sub.I to be at least 5. The largest improvement are reached if
Q.sub.I is at least 10. It must be stated that Q.sub.I may increase
towards infinite, if the layer material is realised with a unique crystal
orientation according to a diffraction intensity I(200) at a vanishing
diffraction intensity I(111). Therefore, there is not set any upper limit
for Q.sub.I which is only set by practicability.
As is known to the skilled artisan, there exists a correlation between
hardness of a layer and stress therein. The higher the stress, the higher
the hardness.
Nevertheless, with rising stress, the adhesion to the tool body tends to
diminish. For the tool according to the present invention, a high adhesion
is rather more important than the highest possible hardness. Therefore,
the stress in the MeX layer is advantageously selected rather at the lower
end of the stress range given below.
These considerations limit in practice the Q.sub.I value exploitable.
In a preferred embodiment of the inventive tool, the MeX material of the
tool is titanium aluminum nitride, titanium aluminum carbonitride or
titanium aluminum boron nitride, whereby the two materials first mentioned
are today preferred over titanium aluminum boron nitride.
In a further form of realisation of the inventive tool, Me of the layer
material MeX may additionally comprise at least one of the elements boron,
zirconium, hafnium, yttrium, silicon, tungsten, chromium, whereby, out of
this group, it is preferred to use yttrium and/or silicon and/or boron.
Such additional element to titanium and aluminum is introduced in the
layer material, preferably with a content i, for which there is valid
0.05 at. %.ltoreq.i.ltoreq.60 at. %,
taken Me as 100 at %.
A still further improvement in all different embodiments of the at least
one MeX layer is reached by introducing an additional layer of titanium
nitride between the MeX layer and the tool body with a thickness d, for
which there is valid
0.05 .mu.m.ltoreq.d.ltoreq.5 .mu.m.
In view of the general object of the present invention, which is to propose
the inventive tool to be manufacturable at lowest possible costs and thus
most economically, there is further proposed that the tool has only one
MeX material layer and the additional layer which is deposited between the
MeX layer and the tool body.
Further, the stress .sigma. in the MeX is preferably selected to be
1 GPa.ltoreq..sigma..ltoreq.4 GPa, thereby most preferably
within the range
1.5 GPa.ltoreq..sigma..ltoreq.2.5 GPa.
The content x of titanium in the Me component of the MeX layer is
preferably selected to be
70 at %.gtoreq.x.gtoreq.40 at %, thereby in a further
preferred embodiment within the range
65 at %.gtoreq.x.gtoreq.55 at %.
On the other hand, the content y of aluminum in the Me component of the MeX
material is preferably selected to be
30 at %.ltoreq.y.ltoreq.60 at %, in a further preferred embodiment even to
be
35 at %.ltoreq.y.ltoreq.45 at %.
In a still further preferred embodiment, both these ranges, i.e. with
respect to titanium and with respect to aluminum are fulfilled.
The deposition, especially of the MeX layer, may be done by any known
vacuum deposition technique, especially by a reactive PVD coating
technique, as e.g. reactive cathodic arc evaporation or reactive
sputtering. By appropriately controlling the process parameters, which
influence the growth of the coating, the inventively exploited Q.sub.I
range is realised.
To achieve excellent and reproducible adhesion of the layers to the tool
body a plasma etching technology was used, as a preparatory step, based on
an Argon plasma as described in U.S. Pat. No. 5,709,784.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing the relationship between nitrogen partial
pressure and bias voltage of the tool body as applied for reactive
cathodic arc eruption in accordance with the present invention;
FIG. 2 is a diagram showing the relationship between typical intensity and
diffraction angle <.theta. where the titanium aluminum nitride layer is
deposited in the Q.sub.I .gtoreq.1 Region;
FIG. 3 is a diagram similar to FIG. 2 but with the layer deposited on a
Q.sub.I .ltoreq.1 region; and
FIG. 4 is a diagram similar to FIGS. 2 and 3 for the working point P.sub.1
in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES 1
An arc ion plating apparatus using magnetically controlled arc sources as
described in Appendix A was used operated as shown in table 1 to deposit
the MeX layer as also stated in table 1 on cemented carbide inserts. The
thickness of the MeX layer deposited was always 5 .mu.m. Thereby, in the
samples Nr. 1 to 7, the inventively stated Q.sub.I values where realised,
whereas, for comparison, in the samples number 8 to 12 this condition was
not fulfilled. The I(200) value was always significantly larger than 20
times the noise average value, measured according to MS. The coated
inserts were used for milling under the following conditions to find the
milling distance attainable up to delamination. The resulting milling
distance according to the lifetime of such tools is also shown in table
______________________________________
Test cutting conditions:
______________________________________
Material being cut: SKD 61 (HRC45)
Cutting speed: 100 m/min
Feed speed: 0.1 m/edge
Depth of cut: 2 mm
______________________________________
The shape of the inserts coated and tested was in accordance with SEE 42 TN
(G9).
It is clearly recognisable from table 1 that the inserts, coated according
to the present inventino, are significantly more protected against
delamination than the inserts coated according to the comparison
conditions.
Further, the result of sample 7 clearly shows that here the stress and thus
hardness of the layer was reduced, leading to lower cutting distance than
would be expected for a high Q.sub.I of 22.5, still fulfilling the
stress-requirements as defined above.
TABLE 1
__________________________________________________________________________
Attainable
Cutting Dis-
Coating Conditions tance (m)
Bias Arc Q.sub.1 = (distance
Voltage
N.sub.2 pressure
Current I(200)/
Residual
till delami-
Sample No.
(-V)
(mbar)
(A) Layer
x y I(111)
Stress GPA
nation)
Remarks
__________________________________________________________________________
Present
1 60 2.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
1.5 5.2 2.2 m (2.1 m)
Invention
2 60 8.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
6.7 4.8 2.8 m (2.5 m)
3 40 2.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
8.1 4.2 8.8 m (8.5 m)
face
lapping
4 40 3.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.4
0.6
10.2
3.9 3.9 m (3.5 m)
5 40 0.5 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
6.0 5.8 2.0 m (1.7 m)
6 30 2.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
15.4
2.5 4.2 m (4.0 m)
7 20 2.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
22.5
1.2 3.3 m (3.3 m)
Comparison
8 60 0.5 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
0.8 6.1 1.0 m (0.8 m)
9 100 2.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
0.7 5.5 0.9 m (0.9 m)
10
100 3.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
0.9 4.8 0.8 m (0.7 m)
11
150 2.0 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.5
0.5
0.2 7.2 0.1 m (0.1 m)
12
100 0.5 .times. 10.sup.-2
150 (Ti.sub.x Al.sub.y)N
0.4
0.6
0.1 6.8 0.2 m (0.1 m)
__________________________________________________________________________
EXAMPLES 2
The apparatus as used for coating according to Example 1 was also used for
coating the samples Nr. 13 to 22 of table 2. The thickness of the overall
coating was again 5 .mu.m. It may be seen that in addition to the coating
according to Example 1 there was applied an interlayer of titanium nitride
between the MeX layer and the tool body and an outermost layer of the
respective material as stated in table 2. The condition with respect to
I(200) and average noise level, measured according to MS was largely
fulfilled.
It may be noted that provision of the interlayer between the MeX layer and
the tool body already resulted in a further improvement. An additional
improvement was realised by providing an outermost layer of one of the
materials titanium carbonitride, titanium aluminum oxinitride and
especially with an outermost layer of aluminum oxide. Again, it may be
seen that by realising the inventively stated Q.sub.I values with respect
to the comparison samples number 19 to 22, a significant improvement is
realised.
The outermost layer of aluminum oxide of 0.5 .mu.m thickness, was formed by
plasma CVD.
The coated inserts of cemented carbide were tested under the same cutting
conditions as those of Example 1, Q.sub.I was measured according to MS.
TABLE 2
__________________________________________________________________________
Inter- Q.sub.1 =
Attainable Cutting
layer Outermost
I(200)/
Distance (m) (distance
Sample No.
(.mu.m
TiAl Layer
x y Layer
I(111)
till delamination)
__________________________________________________________________________
Present
13
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
-- 1.5 4.5 m (4.2)
Invention
(0.4 .mu.m)
(4.6 .mu.m)
14
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
TiCN 7.2 7.8 (7.6 m)
(0.4 .mu.m)
(4.1 .mu.m)
(0.5 .mu.m)
15
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
TiCN 6.8 6.0 m (5.5 m)
(0.4 .mu.m)
(4.4 .mu.m)
(0.5 .mu.m)
16
TiCN (Ti.sub.x Al.sub.y)N
0.5
0.5
(TiAl)NO
5.2 6.2 m (6.0 m)
(0.4 .mu.m)
(4.1 .mu.m)
(0.5 .mu.m)
17
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
Al.sub.2 O.sub.3
12.5
10.1 m (9.8 m)
(0.4 .mu.m)
(4.1 .mu.m)
(0.5 .mu.m)
18
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
Al.sub.2 O.sub.3
7.0 9.8 m (9.5 m)
(0.4 .mu.m)
(4.1 .mu.m)
(0.5 .mu.m)
Comparison
19
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
-- 0.8 1.5 m (1.2 m)
20
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
TiCN 0.8 1.9 m (1.5 m)
21
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
TiCN 0.7 1.8 m (1.5 m)
22
TiN (Ti.sub.x Al.sub.y)N
0.5
0.5
(TiAl)NO
0.1 0.6 m (0.4 m)
__________________________________________________________________________
EXAMPLE 3
Again, cemented carbide inserts were coated with the apparatus of Example 1
with the MeX layer as stated in table 3, still fulfilling the Q.sub.I
conditions as inventively stated and, by far, the condition of I(200) with
respect to average noise level, measured according to MS. Thereby, there
was introduced one of zirconium, hafnium, yttrium, silicon and chromium,
with the amount as stated above, into Me.
The coated inserts were kept in an air oven at 750.degree. C. for 30 min.
for oxidation. Thereafter, the resulting thickness of the oxide layer was
measured. These results are also shown in table 3. For comparison, inserts
coated inventively with different Me compounds of the MeX material were
equally tested. It becomes evident that by adding any of the elements
according to samples 23 to 32 to Me, the thickness of the resulting oxide
film is significantly reduced. With respect to oxidation the best results
were realised by adding silicon or yttrium.
It must be pointed out, that it is known to the skilled artisan, that for
the MeX material wear resistant layers there is valid: The better the
oxidation resistance and thus the thinner the resulting oxide film, the
better the cutting performance.
TABLE 3
__________________________________________________________________________
Thickness of
Sample No. Layer Composition
w x y z Oxide Film (.mu.m)
__________________________________________________________________________
Present
23 (Ti.sub.x Al.sub.y Y.sub.z)N
0.48
0.5
0.02
0.7
Invention
24 (Ti.sub.x Al.sub.y Cr.sub.z)N
0.48
0.5
0.02
0.9
25 (Ti.sub.x Al.sub.y Zr.sub.z)N
0.48
0.5
0.02
0.7
26 (Ti.sub.x Al.sub.y Y.sub.z)N
0.25
0.5
0.25
0.1
27 (Ti.sub.x Al.sub.y Zr.sub.z)N
0.25
0.5
0.25
0.5
28 (Ti.sub.z Al.sub.y W.sub.z)N
0.4
0.5
0.1
0.8
29 (Ti.sub.x Al.sub.y Si.sub.z)N
0.4
0.5
0.1
0.1
30 (Ti.sub.x Al.sub.y Si.sub.z)N
0.48
0.5
0.02
0.2
31 (Ti.sub.x Al.sub.y Hf.sub.z)N
0.4
0.5
0.1
0.9
32 (Ti.sub.x Al.sub.y Y.sub.z Si.sub.w)N
0.1
0.3
0.5
0.1
0.05
Comparison
33 (Ti.sub.x Al.sub.y)N
0.4
0.6 1.8
34 (Ti.sub.x Al.sub.y Nb.sub.z)N
0.4
0.5
0.1
2.5
35 (Ti.sub.x Al.sub.y Ta.sub.z)N
0.4
0.5
0.1
3.3
__________________________________________________________________________
EXAMPLE 4
An apparatus and a coating method as used for the samples of Example 1 was
again used.
HSS drills with a diameter of 6 mm were coated with a 4.5 .mu.m MeX and a
TiN interlayer was provided between the MeX layer and the tool body, with
a thickness of 0.1 .mu.m. The test condition were.
Tool: HSS twist drill, dia. 6 mm
Material: DIN 1.2080 (AISI D3)
Cutting parameters:
v.sub.c =35 m/min
f=0.12 mm/rev.
15 mm deep blind holes with coolant.
TABLE 4
__________________________________________________________________________
Bias
N.sub.2 -
Arc Number of
Voltage
Pressure
current
inter- Residual
drilled
(-V)
(mbar)
(A) layer
layer x y z Q.sub.1
Stress (GPa)
holes
__________________________________________________________________________
Present
36
40 3.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4 5.4
2.1 230
Invention 0.1 .mu.m
37
40 3.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y B.sub.z)N
0.58
0.4
0.02
3.8
2.3 190
0.1 .mu.m
Comparsion
38
150 1.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4 0.03
4.5 10
0.1 .mu.m
39
150 1.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y B.sub.z)N
0.58
0.4
0.02
0.1
4.8 38
0.1 .mu.m
__________________________________________________________________________
The lifetime of the tool was determined by the number of holes which could
be drilled before failure of the drill.
The results of the inventively coated drills are shown as samples No. 36
and 37 in Table 4, the samples No. 38 and 39 again show comparison
samples. Again, I(200) exceeded 20 times intensity average noise level by
far, for samples 36, 37, as measured by MS.
EXAMPLE 5
Again, the apparatus and method as mentioned for Example 1 was used for
coating HSS roughing mills with a diameter of 12 mm with a 4.5 .mu.m MeX
layer. There was provided a titanium nitride interlayer with a thickness
of 0.1 .mu.m between the MeX layer and the tool body. The test conditions
were:
______________________________________
Tool: HSS roughing mill, dia. 12 mm
z = 4
Material: AISI H13 (DIN 1.2344)
640 N/mm.sup.2
Cutting parameters:
v.sub.c = 47.8 m/min
f.sub.t = 0.07 mm
a.sub.p = 18 mm
a.sub.a = 6 mm
climb milling, dry.
______________________________________
The HSS roughing mill was used until an average width of flank wear of 0.2
mm was obtained.
Sample No. 40 in Table No. 5 shows the results of the inventively coated
tool, sample 41 is again for comparison. Again, I(200) of sample Nr. 40
fulfilled the condition with respect to noise, as measured by MS.
TABLE 5
__________________________________________________________________________
Bias
N.sub.2 -
Arc Cutting
Volatge
Pressure
current
inter- Residual
distance
(-V)
(mbar)
(A) layer
layer
x y Q.sub.1
Stress (GPa)
(m)
__________________________________________________________________________
Present
40
40 3.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4
5.4
2.1 35 m
Invention 0.1 .mu.m
Comparison
41
150 1.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4
0.03
4.5 11 m
0.1 .mu.m (chipping
and pee-
ling off)
__________________________________________________________________________
EXAMPLE 6
Again, the apparatus and coating method according to Example 1 was used.
Solid carbide end mills with a diameter of 10 mm with 6 teeth were coated
with a 3.0 .mu.m MeX layer. There was provided a titanium nitride
interlayer with a thickness of 0.08 .mu.m between the MeX and the tool
body. Test conditions for the end mills were:
______________________________________
Tool: Solid carbide end mill, dia. 10 mm
z = 6
Material: AISI D2 (DIN 1.2379)
60 HRC
Cutting parameters:
v.sub.c = 20 m/min
f.sub.t = 0.031 mm
a.sub.p = 15 mm
a.sub.c = 1 mm
Climb milling, dry
______________________________________
The solid carbide end mills were used until an average width of flank wear
of 0.20 mm was obtained. It is to be noted that solid carbide end mills do
no belong to that group of tool which is inventively coated with a hard
material layer having Q.sub.I .gtoreq.1. From the result in Table 6 it may
clearly be seen that for this kind of tools Q.sub.I >1 does not lead to an
improvement. Again, the I(200) to noise condition, measured with MS, was
fulfilled for sample No. 42, for sample No. 43 the I(111) to noise
condition was fulfilled.
TABLE 6
__________________________________________________________________________
Bias
N.sub.2 -
Arc Cutting
Volatge
Pressure
current
inter- Residual
distance
(-V)
(mbar)
(A) layer
layer
x y Q.sub.1
Stress (GPa)
(m)
__________________________________________________________________________
Present
42
40 3.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4
5.0
2.2 17 m
Invention 0.08 .mu.m
Comparison
43
150 1.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4
0.05
4.7 32 m
0.08 .mu.m
__________________________________________________________________________
EXAMPLE 7
Again, an apparatus and method as used for the samples of Example 1 were
used.
Solid carbide drills with a diameter of 11.8 mm were coated with a 4.5
.mu.m MeX layer. There was provided a TiN interlayer between the MeX layer
and the tool body.
______________________________________
Test conditions:
______________________________________
Tool: Solid carbide drill, diam. 11.8 mm
Workpiece: Cast iron GG25
Machining conditions:
v.sub.c = 110 m/min
f = 0.4 mm/rev.
Blind hole 3 .times. diam.
No coolant
______________________________________
The solid carbide drills were used until a maximum width of flank wear of
0.8 mm was obtained. The I(200) to noise condition was again fulfilled,
measured with MS.
TABLE 7
__________________________________________________________________________
Bias
N.sub.2 -
Arc Drilling
Volatge
Pressure
current
inter- Residual
distance
(-V)
(mbar)
(A) layer
layer
x y Q.sub.1
Stress (GPa)
(m)
__________________________________________________________________________
Present
44
40 3.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4
5.4
2.1 95 m
Invention 0.1 .mu.m
Comparison
45
150 1.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4
0.03
4.5 48.5 m
0.1 .mu.m
__________________________________________________________________________
EXAMPLE 8
Again, the apparatus and method as stated in Example 1 were used. Cemented
carbide inserts for turning with a shape in accordance with CNGP432 were
coated with a 4.8 .mu.m MeX layer. There was provided a TiN interlayer
with a thickness of 0.12 .mu.m between the MeX layer and the tool body.
The test conditions were:
______________________________________
Tool: Carbide insert (CNGP432)
Material: DIN 1.4306 (X2CrNi 1911)
Cutting parameters:
v.sub.c = 244 m/min
f = 0.22 mm/rev.
a.sub.p = 1.5 mm
with emulsion
______________________________________
The tool life was evaluated in minutes. The indicated value is an average
of three measurements. Again, I(200)/noise condition, measured with MS,
was fulfilled.
TABLE 8
__________________________________________________________________________
Bias
N.sub.2 -
Arc
Volatge
Pressure
current
inter- Residual
Tool life
(-V)
(mbar)
(A) layer
layer
x y Q.sub.1
Stress (GPa)
(min)
__________________________________________________________________________
Present
46
40 3.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4
5.8
1.9 18.1 m
Invention 0.12 .mu.m
Comparison
47
150 1.0 .times. 10.sup.-2
200 TiN (Ti.sub.x Al.sub.y)N
0.6
0.4
0.04
4.9 5.5 min
0.12 .mu.m
__________________________________________________________________________
In FIG. 1 there is shown, with linear scaling a diagram of nitrogen partial
pressure versus bias voltage of the tool body as applied for reactive
cathodic arc evaporation as the reactive PVD deposition method used to
realise the Examples which were discussed above.
All the process parameters of the cathodic arc evaporation process, namely
arc current;
process temperature;
deposition rate;
evaporated material;
strength and configuration of magnetic field adjacent the arc source;
geometry and dimensions of the process chamber and of the workpiece tool to
be treated
were kept constant. The remaining process parameters, namely partial
pressure of the reactive gas--or total pressure--and bias voltage of the
tool body to be coated as a workpiece and with respect to a predetermined
electrical reference potential, as to the ground potential of the chamber
wall, were varied.
Thereby, titanium aluminum nitride was deposited. With respect to reactive
gas partial pressure and bias voltage of the tool body, different working
points were established and the resulting Q.sub.I values at the deposited
hard material layers were measured according to MS.
It turned out that there exists in the diagram according to FIG. 1 and area
P, which extends in a first approximation linearly from at least adjacent
the origin of the diagram coordinates, wherein the resulting layer lead to
very low XRD intensity values of I(200) and I(111). It is clear that for
exactly determining the limits of P, a high number of measurements will
have to be done. Therein, none of the I(200) and I(111) intensity values
is as large as 20 times the average noise level, measured according to MS.
On one side of this area P and as shown in FIG. 1 Q.sub.I is larger than 1,
in the other area with respect to P, Q.sub.I is lower than 1. In both
these areas at least one of the values I(200), I(111) is larger than 20
times the average noise level, measured according to MS.
As shown with the arrows in FIG. 1, diminishing of the partial pressure of
the reactive gas--or of the total pressure if it is practically equal to
the said partial pressure--and/or increasing of the bias voltage of the
tool body being coated, leads to reduction of Q.sub.I. Thus, the inventive
method for producing a tool which comprises a tool body and a wear
resistant layer system, which latter comprises at least one hard material
layer, comprises the steps of reactive PVD depositing the at least one
hard material layer in a vacuum chamber, thereby preselecting process
parameter values for the PVD deposition process step beside of either or
both of the two process parameters, namely of partial pressure of the
reactive gas and of bias voltage of the tool body. It is one of these two
parameters or both which are then adjusted for realising the desired
Q.sub.I values, thus, and according to the present invention, bias voltage
is reduced and/or partial reactive gas pressure is increased to get
Q.sub.I values, which are, as explained above, at least larger than 1,
preferably at least larger than 2 or even 5 and even better of 10. Beside
the inventively exploited Q.sub.I value, in this "left hand" area, with
respect to P, I(200) is larger, mostly much larger than 20 times the
average noise level of intensity, measured according to MS.
In FIG. 2 a typical intensity versus angle 2.theta. diagram is shown for
the titanium aluminum nitride hard material layer deposited in the Q.sub.I
.gtoreq.1 region according to the present invention of FIG. 1, resulting
in a Q.sub.I value of 5.4 The average noise level N.sup.* is much less
than I(200)/20. Measurement is done according to MS.
In FIG. 3 a diagram in analogy of that in FIG. 2 is shown, but the titanium
aluminum nitride deposition being controlled by bias voltage and nitrogen
partial pressure to result in a Q.sub.I .gtoreq.1. The resulting Q.sub.I
value is 0.03. Here the I(111) value is larger than the average noise
level of intensity, measured according to MS.
Please note that in FIG. 1 the respective Q.sub.I values in the respective
regions are noted at each working point measured (according to MS).
In FIG. 4 a diagram in analogy to that of the FIGS. 2 and 3 is shown for
working point P.sub.1 of FIG. 1. It may be seen that the intensities
I(200) and I(111) are significantly reduced compared with those in the
area outside P. None of the values I(200) and I(111) reaches the value of
20 times the noise average level N.sup.*.
Thus, by simply adjusting at least one of the two Q.sub.I -controlling
reactive PVD process parameters, namely of reactive gas partial pressure
and of workpiece bias voltage, the inventively exploited Q.sub.I value is
controlled.
In FIG. 1 there is generically shown with .delta.Q.sub.I <0 the adjusting
direction for lowering Q.sub.I, and it is obvious that in opposite
direction of adjusting the two controlling process parameters, and
increase of Q.sub.I is reached.
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